Short Information about the Invention as System Controlled Access (SCA)
The system controlled access is designed by several coordinated steps. Actions are taken at the road net on different distances from the given access point. Far upstream, traffic control actions are introduced, that e g might limit average flows in to SCA, i e for an average time period, some minutes or less, a controlled amount of cars will arrive. During the travel towards the motorway access, those cars however might pack together to various dense "car-packets", which implies that during short time periods of less than a minute, large differences from the average flow might arise. Those differences have to be considered at e g closer positioned accesses, not allowing many cars at the access at the same time as there are a package of dense traffic on the motorway. Otherwise all the cars haven't space enough for weaving, and the traffic collapses resulting in queue build up and high risk for accidents.
By regulating the access traffic in relation to the motorway traffic, the traffic density is smoothed for the downstream motorway link. However there are many factors working in the opposite direction, why traffic successively will distribute according to statistical distributions. Thus one might measure a certain traffic distribution at one spot on the motorway, which is different from the traffic distribution some kms further downstream. Differences in detailed traffic distribution arise also if there are no access or exits in between. That means that one often has to consider newly and closely arisen variations, when striving for an effective traffic control.
So there is also a need for a final control at the waving area to achieve a safe and efficient traffic access. An important part of the invention considers that last phase of the access control.
The invention can be regarded as a system of actions on four different levels. The first level is "Access control along a motorway" and is based on traffic management of a road-network, considering various access roads, as other motorways, connections to city street-network etc.
The second level is "preparatory weaving", which is performed on the motorway upstream exits and access-roads.
The third level is "preparatory actions", which are performed just before the "ramp".
The fourth level is the "local level" at the position of the ramp.
The four levels can work together and combine to an efficient and safe access traffic. But compared to to-day situation, every level by itself can be implemented resulting in improved access control. The invention concerns a system-based improvement of access traffic control, where the different levels can be implemented one by itself, or in combinations to various extent, or successively at different occasions, possibly as steps in a planned expansion, or within a given short time period to obtain a more direct cooperation of the applied levels.